Flat panel displays are widely used in our daily life. An important part of flat panel displays is the display substrate. A conventional display substrate usually includes a transparent substrate and a cover layer. The transparent substrate is divided into a display area and a border area, and the display area is surrounded by the border area. The cover layer is disposed in the border area, and is used primarily for covering signal lines and providing a decorative or protective function.
For producing different product appearances, the border area is required to be black or non-black. When the photo-resist layer is formed on the transparent substrate using a black photo-resist layer, the border area looks black. When the cover layer is formed on the transparent substrate using a black photo-resist layer and a non-black photo-resist layer, and the non-black photo-resist layer is disposed between the black photo-resist layer and the transparent substrate, the non-black photo-resist layer blocks the color of the black photo-resist layer from appearing and makes the border area appear non-black.
However, according to the present disclosure, if the non-black photo-resist layer is not thick enough, the color of the border area becomes too dark. This is especially evident for white border area, which may appear greenish, and the decorative effect can be affected. On the other hand, if the non-black photo-resist layer is sufficiently thick, the entire cover layer may become too thick. Further, the signal lines crossing the boundary between the display area and the border area are likely to break if the cover layer is too thick.